The program is concerned with the development of reactions in the carbohydrate field that are useful for synthesis of structures present in biologically important carbohydrate derivatives. Specific objectives include the development of new routes for chain extension and branching to provide stereochemical control and useful functionality at the chain terminus or branch, together with detailed exploration of the use of acetylenic derivatives in the sugar field, and applications in the synthesis of novel amino sugars and deoxy sugars. The work provides information to be used for modificaton of such carbohydrate antibiotics as streptomycin, lincomycin, kanamycin, and various nucleoside antibiotics and C-nucleosides. BIBLIOGRAPHIC REFERENCES: Derek Horton and Masakatsu Sakata, Reactions of Ethyl 3,5,6,-Tri-0-acetyl-2-S-ethyl-1,2-dithio-alpha-D-mannofuranoside with Halogens, Carbohydr. Res., 39, 67-78 (1975). Stephan Dov Gero, Derek Horton, Anne-Marie Sepulchre, and Joseph D. Wander, A Simple Method for Determining the Configurations of Tertiary Alcoholic Centers in Branched-Chain Carbohydrate Derivatives by Use of Europium (III)-Induced Shifts in the PMR Spectrum, J. Org. Chem., 40, 1061-1066 (1975).